Find the area bounded by the curve

MarkSA

Junior Member
Joined
Sep 8, 2007
Messages
243
Hello,

My problem is:
1) Find the area bounded by the curve x = t - 1/t, y = 1 + 1/t, and y = 2.5

I'm not sure how to begin on this, aside from the fact that an integral will come into play. Would I convert it to cartesian form and then take the integral of that? But i'm not sure where the y = 2.5 comes into play. Also i'm not sure how to find the limits. Could you explain the procedure for this type of problem?
 
That's one way to do it.

Looking at the graph, we have a small region bounded by y=5/2 and the upper hlaf of the hyperbola.

Solve \(\displaystyle y=t+\frac{1}{t}\) for t and sub into x.

Solving y for t we get: \(\displaystyle t=\frac{\sqrt{y^{2}-4}}{2}\)

Sub into x and we get \(\displaystyle x=\frac{\sqrt{y^{2}-4}+y}{2}-\frac{2}{\sqrt{y^{2}-4}+y}\)

Now, if you feel brave, you can integrate: \(\displaystyle \int_{2}^{\frac{5}{2}}\left[\frac{\sqrt{y^{2}-4}+y}{2}-\frac{2}{\sqrt{y^{2}-4}+y}\right]dy\)

I would use technology for this. It is very messy.

There is a way t integrate parametrically. \(\displaystyle \int_{t_{1}}^{t_{2}}ydx\). See here: http://www.mathwords.com/a/area_parametric.htm
 

Attachments

  • hyperbola2.jpg
    hyperbola2.jpg
    23.1 KB · Views: 129
Top